526535 5520twf . doc/ 006 A ' B7 五、發明説明（/ ) 本發明是有關於一種光罩圖案的校正方法與裝置，且 特別是有關於一種降低光罩上密集圖案與疏鬆圖案之間偏 差的方法與裝置。 微影（photol 1 thography)可以說是整個半導體製程 .中，最舉足輕重的步驟的步驟之一，凡是與M0S元件結構 相關的，例如：各層的圖案（pat tern)，及摻有雜質（dopant s) 的區域，都是由微影這個步驟來定義的。因此我們通常以 一個製程所需要經過的微影次數，或是所需要的光罩數 量，來表示這個製程的難易程度。而整個半導體工業的元 件積集度（integration)增加，往0.25um以下或更小的線 寬進行，也取決於微影製程技術的發展；所以光罩圖案轉 移（t r an s f e r)的精確性（f i de 1 i t y)便佔了非常重要的地 位，圖案的轉移不正確，則會影響晶片上之關鍵尺寸 (critical dimension, CD)的容忍度（tolerance)，降低 解析度。 鄰近效應（proximity effect)是在光罩圖案的轉移 時，影響其投影在晶片表面上關鍵尺寸準確度最大的因 素，此種效應發生在當光束透過光罩上的圖案投影在晶片 上時，因繞射而產生的現象。 請參照第1A圖與第1B圖，其所繪示爲一些圖案轉移 時的關鍵尺寸偏差（CD variation)現象，包括線端短縮 (line end shorten)，或是圓形轉角（rounded corner)等 情形。如第1A圖所示，虛線部分10爲欲投影在晶片上的 線形圖案，而斜線部份爲實際得到的圖案12。其在線形圖 (請先閱讀背面之注意事項再填寫本頁) 訂 經濟部智慧財產局員工消費合作社印製 526535 A7 B7 5520twf.doc/006 五、發明説明（上〇 案10的端點，會由於光像差而無法在端點形成完整的圖 形，於是產生好像比原圖案較短縮的線形圖案12，此線端 短縮圖案12爲偏差圖案，並非確實所欲投影在半導體基 底的圖案。 又，如第1B圖所示，虛線部分20爲欲投影在晶片上 的原始圖案，而斜線部份爲實際得到的圖案22。其在圖案 的端點部分也有些會變得較原圖形膨賬，或是轉折圖案之 垂直轉角會圓形化（rounding)，造成平滑之圓形轉角等。 例如在實際圖案22的轉角處24，會產生平滑的圓形轉角 26，稱爲內部鄰近效應（intra-proximity);或是在圖案 彼此相鄰的區域28會有因爲像差而產生的局部膨脹圖形， 稱爲父互鄰近效應（inter-proximity)。上述所產生的偏 差情形都會使光罩圖案在進行轉移時，產生晶片上圖形極 大的誤差。 習知的技術中，提出一種光學鄰近校正法（0PC)，其目 的是用以消除因鄰近效應所造成的關鍵尺寸偏差現象。首 先，將欲曝光在晶片之半導體基底上的原始圖案資料輸入 電腦存檔。然後，利用已有的套裝軟體加以計算修正，得 到一結果圖形，再將此結果圖形輸入電腦存檔。最後將此 結果圖形製作於光罩上，此光罩即爲所求，光束透過此光 罩投影在半導體基底上的圖案與原始圖案約相同。 如第2A至2D圖所示，其所繪示的爲光學鄰近校正法 之示意圖。第2A圖所繪示的爲欲曝光在晶片之半導體基 底上的原始圖案上視示意圖，而第2B圖所繪示的爲實際 4 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） (請先閱讀背面之注意事項再填寫本頁)526535 5520twf.doc / 006 A 'B7 V. Description of the Invention (/) The present invention relates to a method and device for correcting a reticle pattern, and in particular to a method for reducing the deviation between a dense pattern and a loose pattern on a reticle. Method and device. Photolithography (photol 1 thography) can be said to be one of the most important steps in the entire semiconductor manufacturing process. All are related to the structure of the MOS device, such as the pattern of each layer (pattern) and dopant s. The area of) is defined by the lithography step. Therefore, we usually use the number of lithography that a process needs to pass, or the number of photomasks to indicate the difficulty of this process. The integration of components in the entire semiconductor industry increases, and the line width is less than 0.25um or less, which also depends on the development of lithography process technology; so the accuracy of tr an sfer ( fi de 1 ity) occupies a very important position, and the incorrect transfer of the pattern will affect the tolerance of critical dimension (CD) on the wafer and reduce the resolution. Proximity effect is the factor that affects the accuracy of key dimensions projected on the wafer surface when the mask pattern is transferred. This effect occurs when the pattern of the beam through the mask is projected on the wafer. The phenomenon of diffraction. Please refer to FIG. 1A and FIG. 1B, which depict key CD variation phenomena during pattern transfer, including line end shortening, or rounded corners, etc. . As shown in Fig. 1A, the dotted line portion 10 is a linear pattern to be projected on the wafer, and the oblique line portion is the actual pattern 12 obtained. Its online graph (please read the precautions on the back before filling this page) Order printed by the Intellectual Property Bureau Employee Consumer Cooperative of the Ministry of Economic Affairs 526535 A7 B7 5520twf.doc / 006 V. Description of the invention (endpoint of the last case 10, will Because of the aberration of light, a complete pattern cannot be formed at the endpoints, so a linear pattern 12 that appears to be shorter than the original pattern is generated. This line-end shortened pattern 12 is a deviation pattern, and is not a pattern that is actually intended to be projected on a semiconductor substrate. As shown in FIG. 1B, the dashed line portion 20 is the original pattern to be projected on the wafer, and the oblique line portion is the actual pattern 22. The end portion of the pattern may also become slightly larger than the original pattern, or The vertical corners of the turning pattern will be rounded, resulting in smooth rounded corners, etc. For example, at the corner 24 of the actual pattern 22, a smooth rounded corner 26 will be produced, which is called intra-proximity ); Or in areas 28 where the patterns are adjacent to each other, there will be a local expansion pattern due to aberrations, which is called the parent inter-proximity. The above-mentioned deviations will all occur. During the transfer of the photomask pattern, a large error occurs in the pattern on the wafer. In the known technology, an optical proximity correction method (0PC) is proposed, which is used to eliminate the key dimension deviation caused by the proximity effect. First, , The original pattern data to be exposed on the semiconductor substrate of the wafer is entered into the computer for archiving. Then, the existing software package is used for calculation and correction to obtain a result graphic, which is then entered into the computer for archiving. Finally, the result graphic is made On the reticle, this reticle is what you want, and the pattern of the beam projected on the semiconductor substrate through the reticle is about the same as the original pattern. As shown in Figures 2A to 2D, it shows the optical proximity correction method Figure 2A is a schematic view of the original pattern to be exposed on the semiconductor substrate of the wafer, and Figure 2B is an actual 4 paper size applicable to the Chinese National Standard (CNS) A4 specification ( 210X297 mm) (Please read the notes on the back before filling this page)
、1T 經濟部智慧財產局員工消費合作社印製 526535 5520twf . doc/006 A7 B7 五、發明説明（彡） 投影在半導體基底上的偏差圖案上視示意圖。然後，第2C 圖所繪示的爲光學鄰近校正法由電腦計算修正後的校正圖 形上視示意圖。接著，將校正圖形形成於光罩上，此光罩 即爲所求，理論上光束透過此光罩投影在半導體基底上的 .結果圖案與第2A圖的原始圖案會大約相同，如第4D圖所 示，其爲經由光學鄰近校正法修正後在半導體基底上所投 影而得的結果圖案，與第2A圖，的圖案非常相似。 但是，因爲每種步進機台的傳遞函數（transfer function)不相同，因此利用此種光學鄰近校正法製作的 光罩，必舉隨著使用的步進機台的不同而有不同的設計。 此外，當曝光條件產生偏差時，光學鄰近校正法都無法做 更進一步的修正，使得圖形仍具有嚴重的關鍵尺寸偏差現 象（CD Var i at ion) 〇 有鑑於此，本發明提供一種改善密集圖案與疏鬆圖案 之間偏差的方法與裝置，由於疏密圖案之間的傳遞函數具 有不同的頻率響應（frequency response)，其強度也有所 不同，通常密集圖案頻率響應於高頻，而疏鬆圖案頻率響 應於低頻，因此在疏密圖案之間便會有些許的偏差。傳統 在利用光學鄰近校正法設計光罩時，並不會考慮到疏密圖 案之間的傳遞函數表現的差異程度’本發明在光罩與成像 之間加上一個衰減器，使通過光罩上疏鬆圖案的光線強度 可以減弱，使成像的光線強度與通過光罩上密集圖案的光 線強度相同，以此消除曝光時疏密圖案之間因爲光強度差 異產生的的偏差。 5 本紙張尺度適用中國國家標準（CNS ) A4規格（210X 297公釐） (請先閱讀背面之注意事項再填寫本頁)Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs, 1T 526535 5520twf .doc / 006 A7 B7 V. Description of the invention (彡) A schematic diagram of the deviation pattern projected on the semiconductor substrate. Then, Fig. 2C shows the top view of the correction pattern after the computer calculates the correction using the optical proximity correction method. Next, the correction pattern is formed on a photomask. This photomask is required. Theoretically, the light beam is projected on the semiconductor substrate through this photomask. The resulting pattern will be approximately the same as the original pattern in Figure 2A, as shown in Figure 4D. As shown, it is the resulting pattern projected on the semiconductor substrate after being corrected by the optical proximity correction method, and is very similar to the pattern in FIG. 2A. However, since the transfer function of each type of stepping machine is different, the photomask made by this optical proximity correction method must have a different design depending on the stepping machine used. In addition, when there is a deviation in the exposure conditions, the optical proximity correction method cannot make further corrections, so that the graphic still has a serious critical dimension deviation phenomenon (CD Var i at ion). In view of this, the present invention provides an improved dense pattern The method and device for the deviation from the loose pattern, because the transfer function between the dense patterns has different frequency responses, and their strengths are also different. Usually, the dense pattern frequency responds to high frequencies, and the loose pattern frequency response At low frequencies, there will be a slight deviation between the dense and dense patterns. Traditionally, when designing a photomask using an optical proximity correction method, the degree of difference in transfer function performance between dense patterns is not taken into account. The present invention adds an attenuator between the photomask and the image to pass through the photomask. The light intensity of the sparse pattern can be reduced, so that the intensity of the imaged light is the same as the intensity of the light passing through the dense pattern on the reticle, thereby eliminating the deviation caused by the difference in light intensity between the sparse pattern during exposure. 5 This paper size applies to China National Standard (CNS) A4 (210X 297mm) (Please read the precautions on the back before filling this page)
I 經濟部智慧財產局員工消費合作社印製 5 經濟部智慧財產局員工消費合作社印製 5520twf.doc/006 A/ _____B7_--- 五、發明説明（0 ) 本發明所提供的衰減器設計係在光罩與成像之間’ A 經過的路徑上加上一個濾波器，濾波器包括兩個虛域’ 個爲透光區域，另一個爲衰減區域，利用在濾波器上鑛 可使穿透光強度減弱的材料，藉以降低低頻區域的響應弓虽 度’使高頻區域與低頻區域的響應強度相同。 爲讓本發明之上述目的、特徵、和優點能更明顯易懂’ 下文特舉一較佳實施例，並配合所附圖式，作詳細說明如 下： 圖式之簡單說明： 第1A圖與第1B圖，其所繪示爲一些圖案轉移時的關 鍵尺寸偏差現象； 第2A至2D圖其所繪示的爲光學鄰近校正法之示意圖； 第3圖爲密集圖案與疏鬆圖案的簡示圖； 第4圖繪示爲疏密圖案之間的頻率響應的關係圖； 第5圖爲依照本發明一較佳實施例的一種衰減器的設 計； 第6圖爲依照本發明一較佳實施例，使用衰減器調整 頻率響應強度後，疏密圖案之間的頻率響應與強度的關係 圖；以及 第7圖繪示爲依照本發明一較佳實施例，衰減器、光 罩與像之間的關係。 圖示標記說明： 10,20 欲投影在晶片上的線形圖案 12,22 投影在晶片上的實際圖案 6 本紙張尺度適用中國國家榡準（CNS ) Α4規格（210X297公釐） IP n·—— n n n 111 I — - - 81 - - I C請先聞讀背面之泣意事項存填寫本頁)I Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 5 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 5520twf.doc / 006 A / _____ B7 _--- 5. Description of the Invention (0) The design of the attenuator provided by the present invention is A filter is added to the path between 'A' and the mask. The filter includes two imaginary domains. One is a light-transmitting area and the other is an attenuation area. The intensity of the light can be penetrated by using the filter on the filter. The weakened material, by which the response bow in the low frequency region is reduced, so that the response intensity in the high frequency region and the low frequency region are the same. In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible ', a preferred embodiment is given below and described in detail with the accompanying drawings as follows: Brief description of the drawings: FIG. 1A and FIG. Figure 1B, which shows the key dimension deviation phenomenon when some patterns are transferred; Figures 2A to 2D, which are schematic diagrams of the optical proximity correction method; Figure 3, which is a simplified diagram of dense patterns and loose patterns; FIG. 4 is a diagram showing the frequency response between the dense and dense patterns; FIG. 5 is a design of an attenuator according to a preferred embodiment of the present invention; and FIG. 6 is a preferred embodiment according to the present invention. The relationship between the frequency response and the intensity between the dense and dense patterns after the frequency response intensity is adjusted using the attenuator; and FIG. 7 shows the relationship between the attenuator, the mask, and the image according to a preferred embodiment of the present invention . Description of pictograms: 10,20 Linear pattern to be projected on the wafer 12,22 Actual pattern projected on the wafer 6 This paper size applies to China National Standard (CNS) Α4 specification (210X297 mm) IP n · —— nnn 111 I —--81--IC Please read and read the Weeping Notes on the back and fill in this page)
、1T 線翻！ 526535 A7 B7 5520twf.doc/006 五、發明説明（f) 24 轉角處 26 圓形轉角 . 28 圖案相鄰的區域 32a 密集圖案 32b 疏鬆圖案 d2 圖案之間的距離 40 透鏡主體 42a 透光區 42b 哀減區 50 光罩 52 衰減器 54 成像 實施例 請參照第3圖其繪示爲密集圖案與疏鬆圖案的簡示 圖。其中，由圖即可看出密集圖案32a之間的距離di小於 疏鬆圖案32b之間的距離d2，當光線通過密集圖案32a與 疏鬆圖案32b後，會呈現不同的空間頻率，如第4圖所示。 第4圖繪示爲疏密圖案之間的頻率響應與強度的關係 圖，如圖所示，疏鬆圖案的頻率響應fi較低，但其強度較 高，而密集圖案的頻率響應f2較高，但其強度較弱。如此 的強度差異會在進行微影製程時，造成疏密圖案臨界尺寸 之間的偏差，由於疏鬆圖案的頻率響應^強度較密集圖案 的頻率響應〖2強，因此曝光進行時，當疏鬆圖案曝光達預 定曝光量時，緊密圖案的曝光量會稍微不足，而當緊密圖 7 本紙張尺度適用中國國家標準（CNS ) Α4規格（210X297公釐） (請先閱讀背面之注意事項再填寫本頁), 1T line turn! 526535 A7 B7 5520twf.doc / 006 V. Description of the invention (f) 24 corners 26 circular corners. 28 Pattern adjacent area 32a Dense pattern 32b Dense pattern d2 Distance between patterns 40 Lens body 42a Light transmission area 42b Subtracting area 50, mask 52, attenuator 54. For an imaging example, please refer to FIG. 3, which is a simplified diagram showing a dense pattern and a loose pattern. Among them, it can be seen from the figure that the distance di between the dense patterns 32a is smaller than the distance d2 between the loose patterns 32b. When light passes through the dense pattern 32a and the loose pattern 32b, it will present different spatial frequencies, as shown in Figure 4. Show. Figure 4 shows the relationship between the frequency response and intensity of the dense pattern. As shown in the figure, the frequency response fi of the loose pattern is low, but its intensity is high, and the frequency response of the dense pattern is high f2. But its strength is weak. Such a difference in intensity will cause a deviation in the critical size of the sparse pattern during the lithography process. Because the frequency response of the sparse pattern ^ is stronger than the frequency response of the dense pattern [2], so when the exposure is performed, when the sparse pattern is exposed When the predetermined exposure is reached, the exposure of the compact pattern will be slightly insufficient, and when the compact image is shown in Figure 7, this paper size applies the Chinese National Standard (CNS) Α4 specification (210X297 mm) (Please read the precautions on the back before filling this page)
、1T 經濟部智慧財產局員工消費合作社印製 526535 ， 552〇twf . doc/ 006 A7 B7 五、發明説明（ό) 案曝光量達預定曝光量時，疏鬆圖案便會曝光過度。 -----------Aw-- (請先閲讀背面之注意事項再填寫本頁) 本發明根據頻率響應結果，利用衰減器降低疏鬆圖案 之光強度，以降低其頻率響應，使疏密圖案之間的頻率響 應強度相當，藉以消除疏密圖案之間的偏差，衰減器的設 •計如第5圖所示，提供一濾波器40,包括一正常的透光區 域42a與一衰減區域42b，在欲形成衰減區域42b的中心 鍍上可部分吸收光線，使穿透衰減區域42b的光線強度減 弱的材質，比如爲銀（silver)，降低的程度與鍍上的材質 密度成正比關係。其中，第5圖的衰減器設計僅爲一例子， 在實際的操作上，可以將衰減區域42b設計在透鏡40主 體的任何區域上，目的均在於使通過光罩上某特定區域的 光強度減弱。 -線- 經濟部智慧財產局員工消費合作社印製 第6圖爲依照本發明一較佳實施例使用衰減器調整頻 率響應強度後，疏密圖案之間的頻率響應與強度的關係 圖。在本實施例中，假設通過光罩上疏鬆圖案的光線會經 過光學系統的中心，因此光學系統上衰減器的設計位於光 學系統的中心。加上衰減器的校正以後，通過疏鬆圖案的 光的頻率響應會被降低，調整至與通過密集圖案的光之頻 率響應。 而第7圖所示爲依照本發明一較佳實施例，衰減器52、 罩幕52與成像54之間的關係圖，衰減器52置放在罩幕52 與成像54之間，通過罩幕50的光線若因爲罩幕50上圖 案疏密產生的偏差，可利用衰減器52將頻率響應強度較 大的部分減弱。 8 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） 526535 五、發明説明（q) 本發明在光罩與成像之間加上一個衰減器，使通過光 罩上疏鬆圖案的光線強度可以減弱，使成像的光線強度與 通過光罩上密集圖案的光線強度相同，以此消除曝光時疏 密圖案之間因爲光強度差異產生的的偏差，因此罩幕圖案 .設計不需要因爲使用的步進機台不同可設計不同的光罩。 此外，可以視機台狀況調整衰減器，進一步控制光線減弱 的幅度，因此因爲對焦狀況變動產生的偏差可藉本發明加 以消除。 雖然本發明已以一較佳實施例揭露如上，然其並非用 以限定本發明，任何熟習此技藝者，在不脫離本發明之精 神和範圍內，當可作各種之更動與潤飾，因此本發明之保 護範圍當視後附之申請專利範圍所界定者爲準。 _^ϋ. - - - - -L- 1- —II 1^1 - 匿 I an— n m In >^ϋ (請先閱讀背面之注意事項再填寫本頁) 線®— 經濟部智慧財產局員工消費合作社印製 9 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐）Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs, 1T, 526535, 552 twf.doc / 006 A7 B7 V. Description of Invention (ό) When the exposure of the project reaches a predetermined exposure, the loose pattern will be overexposed. ----------- Aw-- (Please read the notes on the back before filling this page) The present invention uses the attenuator to reduce the light intensity of the loose pattern according to the frequency response result, so as to reduce its frequency response. The frequency response intensity between the dense and dense patterns is made equal to eliminate the deviation between the dense and dense patterns. The design of the attenuator is shown in Fig. 5 and a filter 40 is provided, including a normal light transmitting area 42a and An attenuation region 42b, a material that can partially absorb light at the center of the attenuation region 42b to be formed and can reduce the intensity of light passing through the attenuation region 42b, such as silver, the degree of reduction is proportional to the density of the plated material direct ratio. Among them, the design of the attenuator in FIG. 5 is only an example. In actual operation, the attenuation region 42b can be designed on any area of the main body of the lens 40. The purpose is to weaken the light intensity passing through a specific area on the mask. . -Line- Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. Figure 6 is a graph showing the relationship between the frequency response and intensity between the dense and dense patterns after the frequency response intensity is adjusted using the attenuator according to a preferred embodiment of the present invention. In this embodiment, it is assumed that the light passing through the loose pattern on the reticle passes through the center of the optical system, so the design of the attenuator on the optical system is located at the center of the optical system. After the attenuator correction is added, the frequency response of light passing through the loose pattern is reduced, and adjusted to the frequency response of light passing through the dense pattern. Fig. 7 shows the relationship between the attenuator 52, the mask 52 and the imaging 54 according to a preferred embodiment of the present invention. The attenuator 52 is placed between the mask 52 and the imaging 54 and passes through the mask. If the light at 50 is biased due to the denseness of the pattern on the cover 50, the attenuator 52 can be used to attenuate the portion of the larger frequency response intensity. 8 This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) 526535 V. Description of the invention (q) The present invention adds an attenuator between the photomask and the imaging to make the light passing through the loose pattern on the photomask The intensity can be reduced, so that the intensity of the imaged light is the same as that of the dense pattern passing through the reticle, so as to eliminate the deviation caused by the difference in light intensity between the dense and dense patterns during exposure, so the mask pattern. Different stepping machines can be designed with different photomasks. In addition, the attenuator can be adjusted according to the condition of the machine to further control the attenuation of the light. Therefore, the deviation due to the change in the focus condition can be eliminated by the present invention. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and decorations without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application. _ ^ ϋ.-----L- 1- —II 1 ^ 1-Ian— nm In > ^ ϋ (Please read the precautions on the back before filling this page) Line ®-Intellectual Property Bureau, Ministry of Economic Affairs Printed by Employee Consumer Cooperatives 9 This paper is sized for China National Standard (CNS) A4 (210X297 mm)